This invention relates generally to the field of surgery, and more particularly to the field of vascular microsurgery.
In various surgical procedures, it is necessary to unite or reunite very small blood vessels, nerves and the like. The procedure of joining blood vessels is known as vascular anastomosis. Particularly in neurosurgical procedures and in the reattachment of severed body members, the number of anastomoses required can be very numerous, and accordingly, it is advantageous and frequently necessary to perform each such connection quickly yet properly.
A conventional end-to-end anastomosis is illustrated in FIG. 1, which shows a pair of vessels 1 and 2, each held by a respective clamp 3 or 4 while it is sutured around its circumference. The vessel ends are first approximated by inward traction on the two vascular clamps. The vessels may then be preliminarily interconnected by placing sutures at two, three or four spaced locations around the circumference of the vessel--note the threads 5 and 6 in tension--whereafter the suturing 7 is completed with a needle 8. Various suturing techniques are known, all of which are designed to: (a) provide a leak-proof connection; (b) provide adequate tensile strength; (c) avoid unnecessary restriction of the vessel; (d) avoid unnecessary tearing and other trauma to the vessel; and (e) promote rapid and thorough healing. Some of these objectives become increasingly difficult to satisfy as smaller and smaller anastomoses are carried out; furthermore, the danger of accidentally catching the rear or distal wall of a vessel with the needle as the proximal wall is being sutured increases with diminishing vessel size.
With all vascular suturing techniques, thrombosis or clotting tends to occur at the points of needle penetration. While this clotting would not usually be sufficient to occlude larger vessels, in smaller veins and arteries a significant constriction or complete occlusion of the vessel can result from clotting. In a recent article, the problem was summarized: "It is apparent to us that the damage to vascular endothelium caused by the microvascular needle perforation is considerable. The amount of subsequent platelet aggregation and clot formation can be extensive, and these platelets are known to release vasoactive substances that can alter vessel diameter. This could diminish blood flow through a 1- to 2-mm vascular anastomosis expected to give immediate increased flow to an underperfused region of the brain." D. Pagnanelli et al, The Cutting Edge Microsurgical Needle, Journal of Neurosurgery, volume 59, no. 3, pages 510-512 (Sept. 1983).
In addition to the physiological damage done by suturing, it is also significant that suturing, particularly of small vessels, is a very tedious time-consuming procedure which can preoccupy and fatigue a surgeon over the course of a long procedure. A more rapid way of performing microvascular anastomoses could free the surgeon for other tasks, and could shorten surgical procedures as well. The need for a workable, rapid, non-suturing technique for microsurgery is obvious.
Various non-suture devices and techniques for performing anastomoses are known, particularly for intestinal and colorectal anastomoses, for which various stapling apparatus and methods have been known for some years. Known stapling techniques, however, require penetration of the organ wall, and if applied to vascular anastomoses, the problems of clotting and the like, as described above, could be expected to arise. For vascular anastomosis, various other non-suture mechanical clamps have been suggested. Such clamps frequently include a permanent or sacrificial ferrule or the like and means for clamping the vessel against the ferrule so that penetration of the vessel wall is avoided. However, clamps of this type have not gained widespread acceptance.
In view of the foregoing, this invention has been made with a view to substantially increasing the speed of microvascular anastomoses while avoiding the clotting problems caused by conventional suturing procedures. Another object is to reduce the material costs and duration of microsurgical procedures.
A further object of the invention is to provide a permanently implantable microsurgical clip for use in place of microvascular suturing. Yet another object is to provide the surgeon with a clip that can be easily held and applied during vascular anastomoses.
This invention relates generally to a surgical procedure such as an anastomosis wherein a pair of tissues is approximated, then partially everted, and then joined by placing the legs of a microsurgical clip over the adjoined tissues and crimping the legs about the tissues in such a way as to hold the tissues together without penetrating them.
The invention is particularly directed to a microvascular surgical clip comprising a pair of arcuate legs interconnected by a bridging section and extending in a common direction therefrom, the clip being made of a biologically acceptable material such as a noble metal, which material further must be capable of plastic deformation so that the legs can be crimped together around a pair of adjoined biological tissues. The clip preferably includes also a pair of ears extending from the bridging section in a direction opposite that of the legs. One can spread the legs and thereby release the tissues by applying inward force on the outside of the ears. Furthermore, each ear constitutes a convenient means by which the clip may be held, preferably by a vacuum conduit.
To illustrate the clip application procedure and the usefulness of the ears, also disclosed herein is a tool or tweezers for applying the inventive clip. The tool comprises a pair of interconnected arms capable of pivoting motion with respect to one another. Each arm is curved inwardly at its lower end with the distal portions of the arms directed substantially at one another so that one can crimp a microsurgical clip between the jaws of the tool by applying inward pressure on the arms. A fine suction conduit, connected to the tool and extending generally along a bisector of the two arms, terminates slightly above the point of closure of the distal ends of the arms. The inside diameter of the tube is sized to fit over one of the clip ears whereby the clip can be retained indefinitely at the distal end of the tube by the vacuum therein. This facilitates manipulation of the clip in the surgical field as the clip is positioned astride abutting tissues and then crimped.